Before deploying an Exchange 2007 organization, you must first identify the model that will be deployed. There are four supported Exchange organization models:

• Simple Exchange Organization   The Simple Exchange Organization contains either a single Exchange server that provides all Exchange services and stores all Exchange data for the entire organization, or multiple Exchange servers in a topology that includes redundant directory servers and an Edge Transport server in a perimeter network. For more information, see Planning for a Simple Exchange Organization.
  
  
• Standard Exchange Organization   The Standard Exchange Organization builds upon the Simple Exchange Organization by deploying multiple computers running Exchange. For more information, see Planning for a Standard Exchange Organization.
  
  
• Large Exchange Organization   The Large Exchange Organization is the largest organization model that can be deployed in a single Active Directory directory service forest. For more information, see Planning for a Large Exchange Organization.
  
  
• Complex Exchange Organization   The Complex Exchange Organization is the only model that includes multiple Active Directory forests or the use of synchronization technology. For more information, see Planning for a Complex Exchange Organization.
  
  

We recommend that you deploy a new, single-server Simple Exchange Organization only when you are using Microsoft Windows Small Business Server 2003. We recommend that you deploy a new, multiple-server Simple Exchange Organization only when using Centro.

When deploying a new Standard, Large, or Complex Exchange Organization, we recommend that you use the following process:

• Verify that Active Directory is configured correctly for an Exchange Organization. The requirements that must be met are:
  
  
  • The domain controller that is the schema master has Windows Server 2003 Service Pack 2 (SP2), Windows Server 2003 Service Pack 1 (SP1) or Windows Server 2003 R2 installed. To determine which domain controller is the current schema operations master, see Identify the schema master.
    
    
  • At least one domain controller in each Active Directory site that will contain Exchange 2007 must be running Windows Server 2003 SP2 or Windows Server 2003 SP1. For more information about SP1, including links for downloading or ordering SP1, see Windows Server 2003 SP1 Roadmap. Note that Windows Server 2003 SP2 is the recommended operating system service pack for Windows Server 2003.
    
    
  • The Active Directory domain functional level must be Microsoft Windows 2000 Server-native or higher for all domains in the Active Directory forest where you will install Exchange 2007. For more information about raising the Active Directory domain functional level, see Raise the domain functional level.
    
    
• Verify that your network and its name resolution services are configured correctly for an Exchange organization. The requirements that must be met are:
  
  
  • Domain Name System (DNS) is configured correctly in your Active Directory forest, using a single, unified namespace. For more information about configuring DNS for use with Exchange 2007, see Configuring DNS Settings for Exchange 2007 Servers.
    
    
  • Connection points between distributed sites that will contain Exchange 2007 have at least 64 kilobits per second (Kbps) of bandwidth available.
    
    
  • Verify that Active Directory sites are configured correctly to accommodate message routing. For detailed steps about planning for message routing using Active Directory sites, see Planning to Use Active Directory Sites for Routing Mail.
    
    
• Prepare the Active Directory forest and domains for Exchange 2007. The Active Directory schema needs to be extended to support Exchange 2007. For detailed steps about how to prepare your Active Directory forest and domains for Exchange 2007, see How to Prepare Active Directory and Domains.
  
  

  Note:
  If you are deploying a new Exchange organization based on Exchange 2007 SP1, and you are preparing your Active Directory schema and domains by using a computer running Windows Server 2008, you must first install the Active Directory management tools on Windows Server 2008 prior to preparing the schema or a domain by using the following command: ServerManagerCmd -i RSAT-ADDS

  For more information about preparing the Active Directory schema and domains, see How to Prepare Active Directory and Domains.
  
  
• Deploy and configure Client Access servers. The first Exchange 2007 server role that should be introduced into the organization is the Client Access server. The Client Access server provides access to clients using Post Office Protocol version 3 (POP3), Internet Message Access Protocol version 4 (IMAP4), Microsoft Outlook Anywhere, and ActiveSync. The Client Access server role also provides Web services, including the Availability service and Autodiscover service for clients such as Microsoft Office Outlook 2007. You must deploy the Client Access server role in each Active Directory site that will contain a Mailbox server. For more information about deploying the Client Access server role, see Deploying Server Roles and Finalize Deployment Tasks.
  
  
• Deploy and configure Edge Transport servers. The Edge Transport server is deployed outside the Exchange organization in a perimeter network. You can deploy this server role during any phase of the upgrade process. The Edge Transport server does not depend on any particular messaging or directory configuration. You can add an Edge Transport server to an existing Exchange organization without upgrading any Exchange servers. You do not have to make any organizational changes to use an Edge Transport server. The Edge Transport server uses Active Directory Application Mode (ADAM) for storage of configuration and recipient information. The ADAM schema contains all the object classes and attributes that are required to perform configuration of the Edge Transport server. For more information about deploying the Edge Transport server role and synchronizing ADAM with Active Directory, see Deploying Server Roles and Finalize Deployment Tasks.
  
  
• Deploy and configure Hub Transport servers. The Mailbox server and Unified Messaging server require a Hub Transport server. You must install and configure a Hub Transport server before mail flow can be established. For more information about deploying the Hub Transport server role, see Deploying Server Roles and Finalize Deployment Tasks.
  
  
• Deploy and configure Mailbox servers. For more information about deploying the Mailbox server role, see Deploying Server Roles and Finalize Deployment Tasks.
  
  
• Deploy and configure Unified Messaging servers. The Unified Messaging server is new in Exchange 2007. The Unified Messaging server does not interoperate with earlier versions of Exchange Server. You cannot install and configure a Unified Messaging server until after you have deployed and configured a Hub Transport server and Mailbox server. This is required because messages generated by a Unified Messaging server can only be submitted to a Hub Transport server, and because only recipients who have mailboxes on Exchange 2007 servers can use Unified Messaging. After you install a Unified Messaging server, there are other deployment tasks that you must complete to successfully deploy Unified Messaging in your organization. For more information about deploying the Unified Messaging server role, see Deploying Server Roles and Finalize Deployment Tasks.
  
  
• Perform post-installation tasks. After deployment of server roles is complete, there are several post-installation tasks that you should perform, including verifying that your installations were successful, and finalizing your deployment. For detailed steps about how to verify that Exchange 2007 was successfully installed, see Verifying an Exchange 2007 Installation.